UV-Vis spectrum was utilized to study the aggregation behaviors of H4THPP2+ inDMF-chloroform mixture and water. It was found that J-aggregation of H4THPP2+ was formed inDMF-chloroform mixture and H-aggregate was formed in aqueous solution with highionic-strength, as indicated by different spectral characteristics of different H4THPP2+ aggregates.
The aggregation of meso-tetrakis(4-hydroxyphenyl)porphyrin (H2THPP) in dimethyl- formamide (DMF)-water solution and in DMF-chloroform solution was studied by UV-vis absorption spectroscopy. The red shift of Soret band indicates the formation of J-type aggregates of H2THPP in these two solutions. However, different shift extent of Soret band, 12 nm in DMF-water solution and 32 nm in DMF-chloroform solution, implies structural difference between these two J-type aggregates. The hydrogen bond between hydroxyl group and N-H bonds in porphyrin ring is thought as the main cause to the formation of J-type aggregate in DMF- chloroform solution, whereas the π?σ interaction between two adjacent porphyrin cores is thought as the main cause of the formation of J-type aggregate in DMF-water
